As shown in, e.g., Japanese Patent Laid-open Application No. S56-70784, as for a personal trimming system (a hair clipper), a device in which a head portion pivots with respect to a hand-holdable portion (main body) has been known. FIG. 13 shows a configuration of a conventional hair clipper 100. Referring to FIG. 13, the conventional hair clipper 100 includes an approximately cylindrical hand-holdable portion 110 and a head portion 120 pivotably supported at an upper vicinity of the hand-holdable portion 110.
Provided inside the hand-holdable portion 110 are a motor 111, a driving unit 130 for converting a rotation of a shaft of the motor 111 into a reciprocating motion and a battery 112. The driving unit 130 includes a pinion gear 131 secured to the shaft of the motor 111; a face gear 132 pivoting with respect to a shaft (not shown) provided in a direction perpendicular to the shaft of the motor 111 while being engaged with the pinion gear 131; and a driving connecting piece 133 provided with an opening 133A rotatably insertion-fitted to an eccentric boss 132A provided at the face gear 132. A trimmer blade (not illustrated) is connected to the driving connecting piece 133 and, further, downwardly installed in a direction perpendicular with respect to the page in FIG. 13.
Provided at the upper vicinity of the hand-holdable portion 110 is a spherical shaft 134 having an approximately spherical outer peripheral surface. Further, provided at a lower portion of the head portion 120 is an approximately spherical shaped bearing 121 insertion-fitted to the approximately spherical outer peripheral surface of the spherical shaft 134. In other words, the spherical shaft 134 and the approximately spherical shaped bearing 121 form a spherical shaped bearing, and the head portion 120 is pivotably supported with respect to the hand-holdable portion 110. The face gear 132 is provided at an inner portion of the spherical shaft 134 and, further, a pivoting point (rotational shaft) of the head portion 120 and a rotational shaft of the face gear 132 are provided so that they are coaxial.
In the conventional hair clipper 100, the size of the upper vicinity of the hand-holdable portion 110 is about the size of the lower vicinity of the head portion 120 and, further, the exterior of the hair clipper 100 has been designed primarily for aesthetic consideration. Therefore, it is difficult for a user to know where the head portion 120 pivots. In such case, if the user grips a boundary portion between the hand-holdable portion 110 and the head portion 120, the head portion 120 cannot adequately pivot with respect to the hand-holdable portion 110, thereby conforming improperly to irregularities of the skin. Such a problem occurs in a general personal trimming system such as an electric shaver, an electric toothbrush or the like as well as a hair clipper.